SINGLE-SHOT VERSUS INTERLEAVED ECHO-PLANAR MR-IMAGING - APPLICATION TO VISUALIZATION OF CARDIAC-VALVE LEAFLETS

Visualization of the cardiac valves with standard magnetic resonance (MR) imaging is not adequate because of long acquisition times. Echo-planar imaging (EPI) can, however, be performed with a temporal resolution (30-50 msec) comparable to that of echocardiography. The authors evaluated the feasibility of real-time imaging of cardiac valve motion with ultrafast MR techniques, Eight healthy volunteers and three patients with mitral stenosis and regurgitation were studied with a 1.5-T whole-body imager, Two different EPI sequences were assessed: a standard single-shot gradient-echo EPI (GEPI) sequence and a fast imaging technique based on multiple-shot EPI with interleaved k-space acquisition (IGEPI). Fat-suppressed images with an in-plane resolution of 3.7 x 3.7 mm were obtained equally spaced through the cardiac cycle, Half-k-space acquisition was used, Morphologic evaluation was superior with IGEPI, owing to the better intracavitary signal homogeneity (P<.01), and the mitral valve leaflets were easier to identify on systolic images, IGEPI provided adequate valve visibility in all three patients.